In recent years, a movement has gained traction to replace incandescent light bulbs with lighting fixtures that employ more efficient lighting technologies. One such technology that shows tremendous promise employs light emitting diodes (LEDs). Compared with incandescent bulbs, LED-based light fixtures are much more efficient at converting electrical energy into light and are longer lasting, and as a result, lighting fixtures that employ LED technologies are expected to replace incandescent bulbs in residential, commercial, and industrial applications.
Many of these lighting fixtures employ an array of LEDs, which emit light that is directed through a lens. To help mix the light that is emitted from the various LEDS in the array as well as to hide the LEDs from view, some form of diffusion is employed. Such diffusion may be provided by a separate diffuser that is placed adjacent the lens, applying a diffusive film to the lens, or applying a surface treatment to the lens. While performance of these diffusion techniques is acceptable, there are significant material and manufacturing costs associated with providing a separate diffuser and lens or applying a diffusive film or treatment to the surface of the lens. As such, there is a need for a composite lens that is capable of providing diffusion internally while maintaining the performance of the aforementioned diffusion techniques.